New disease carried by ticks discovered in Missouri

ST. LOUIS — For the second time this summer, Missouri has received national recognition for strange diseases.

A report in July described nine people in St. Louis who developed lung worms after eating raw crawfish on float trips. Now, doctors and scientists have discovered a new disease carried by ticks that infected two farmers from the St. Joseph area.

The newly dubbed Heartland virus can cause high fever, chills, body aches, nausea and diarrhea, according to an article published Thursday in the New England Journal of Medicine.

The investigative trail that led to the discovery of the novel disease started when two men, 57 and 67, who lived on large farms came separately to Heartland Regional Medical Center in St. Joseph in June 2009 complaining of fever, fatigue and a lack of appetite. Neither had a rash, but both men had pulled ticks off their bodies in the previous week.

Dr. Scott Folk suspected the men had ehrlichiosis, a fairly common tick-borne disease in Missouri. There have been about 180 cases in the state so far this year.

But the treatment for ehrlichiosis, a bacterial infection, didn’t do much for the patients. A puzzled Folk sent blood specimens to his colleagues at the Centers for Disease Control and Prevention in Atlanta.

Folk, an infectious disease specialist at Heartland since 1998, has turned to the CDC for its sophisticated lab testing for more than 10 years. His work with two other patients led to a CDC report last year on a rare virus that is spread by inhaling fumes from mice urine.

Folk said he appreciates working with the nation’s top scientists because he can “bring their expertise to the bedsides of patients in small cities.”

The tests on the blood of the two farmers turned up negative for ehrlichiosis and Rocky Mountain spotted fever, another common tick-borne bacterial infection in Missouri. Scientists also didn’t find any evidence of a flu virus.

But after a genetic analysis of the blood cells, they found something different — a virus that belongs to the phlebovirus family of diseases carried by insects but that had not previously been identified.

“I’ve seen unusual infections in the past, but this was something completely new and unique to the world,” Folk said.

The excitement of discovering a new disease was tempered, because two sick men were still in the hospital.

“It was kind of scary as well. We didn’t know what path those patients were going to go down, how sick they were going to become,” Folk said.

Doctors could only treat the men’s symptoms with fluids and pain medicine. One man stayed in the hospital for 10 days, and the other stayed for 12 days as doctors worked to get their blood cell counts back to normal.

Both men recovered fully after six weeks.

The doctors and scientists who worked on the disease investigation decided to name the new virus Heartland, both after the geographic region and the 350-bed hospital where the first patients were treated.

“Many important medical discoveries are made at large academic medical centers in big cities, which only makes sense because that’s where the research capabilities are,” Folk said, “But I think Heartland virus is a good example of the fact that important medical discoveries can be made outside of the ivory towers.”

Since the discovery, Folk has worked with the CDC to identify any other cases of Heartland virus that might have been misdiagnosed in earlier patients who were treated for similar illnesses at area hospitals. Blood samples have been collected from the patients to check for antibodies to the virus.

Researchers from the CDC have also traveled to northwest Missouri to collect ticks and mosquitoes and take blood from farm animals to see if they can find the virus in nature. Test results are expected in the next few months.

Scientists are eager to learn more about the disease, because the experiences of two patients are not enough to know if a typical infection produces mild or serious symptoms. And although the virus is new to scientists, Folk suspects it has been around a while and will continue to infect people.

“It might not be long before you see it in your neck of the woods,” he said. “It’s a good reminder for all of us to make sure we think about tick bite prevention when we go out tromping through the woods.”